1. Field of the Invention
The present invention relates to a crash box for a vehicle, and more particularly, to a crash box for a vehicle which is installed between a side member and a back beam of a bumper which is positioned on a vehicle body to absorb impact energy when a collision occurs.
2. Description of Related Art
Generally, a bumper of a vehicle is installed at a front side and a rear side of the vehicle to protect a vehicle body and a passenger when a front or rear collision occurs and further protects a hood, and an engine and various devices installed in an engine room and the like.
The bumper is provided with a bumper cover that forms an outer shape of the bumper, an energy absorber that dampens impact when a collision occurs and has a shape recovery function after the collision, and a back beam (referred to as “bumper beam”) that supports the energy absorber and is installed on the side member wherein a crash box 3 for absorbing impact energy when a collision occurs is installed between the back beam 1 and the side member 2.
The crash box 3 is configured to absorb impact energy by being compress-deformed in an axial direction (front/rearward) in a case where the impact energy is applied to the bumper and the crash box may be configured to minimize the deformation of the side member so as to minimize a repair cost.
Further, the crash box needs to be configured to satisfy the regulation of the Research Council for Automobile Repairs (RCAR), which is referred to as a representative regulation of the automobile industrial field.
Referring to FIG. 1, in the related art, there existed only a corner test way that evaluates compress-deformation performance by applying an impact D of a diagonal direction to the back beam 1 of a vehicle in a conventional RCAR performance test. However, recently a center test way has been added, which evaluates a load support performance by applying an impact F of an axial direction of a vehicle to a middle portion of the back beam 1.
Meanwhile, a conventional crash box 3 is formed to have cross-section of a circular shape or a quadrangular shape as shown in FIG. 2, or an octagonal shape as shown in FIG. 3, wherein when it is formed to have cross-section of an octagonal shape which has a high sectional coefficient, an RCAR corner test obtains a high performance satisfaction degree.
However, when the crash box 3 is formed to have cross-section of an octagonal shape, it is advantageous for a compress-deformation, but it is disadvantageous in supporting the load, and thus it does not efficiently respond to an RCAR center test. Further, when the crash box 3 is formed to have cross-section of a quadrangular shape, it is advantageous in supporting the load and thus it efficiently responds to an RCAR center test but it is disadvantageous for the compress-deformation and thus it does not efficiently respond to the RCAR corner test.
Accordingly, there needs to be developed a crash box having an optimum shape which is advantageous in responding to both the RCAR corner test and RCAR center test.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.